Transvenous Extraction Performance of Expanded Polytetrafluoroethylene Covered ICD Leads in Comparison to Traditional ICD Leads in Humans ANDREA DI CORI, M.D., MARIA GRAZIA BONGIORNI, M.D., GIULIO ZUCCHELLI, M.D., PH.D., LUCA SEGRETI, M.D., STEFANO VIANI, M.D., LUCA PAPERINI, M.D., and EZIO SOLDATI, M.D. From the Division of Cardiovascular Diseases 2, Santa Chiara Hospital, University of Pisa, Pisa, Italy
Background: In the Endotak Reliance G defibrillating leads (Guidant Corporation, St. Paul, MN, USA), coils are covered with expanded polytetrafluoroethylene (ePTFE) to prevent tissue ingrowth. The aim of the study was to evaluate transvenous extraction performance, outcomes, and fibrotic adherences rate of ePTFE defibrillating leads in comparison to traditional non-ePTFE cardiac defibrillator (ICD) leads. Methods: Seventeen consecutive ICD recipients (ePTFE Group A, 16 men, mean age 66 ± 12 years) with 17 Endotak Reliance G dual-coil ICD leads (mean implantation time 23 ± 26 months) underwent a transvenous removal procedure. They were compared with two control groups, including 20 Sprint Quattro 6944 (non-ePTFE Group B; Medtronic Inc., Minneapolis, MN, USA) and 36 Riata 1570 ICD leads (non-ePTFE Group C; St. Jude Medical, St. Paul, USA). The indication for lead extraction was local infection in 35 patients (48%), sepsis in 24 patients (33%), and lead malfunction in 14 patients (19%). Results: In all groups, all leads were successfully and completely removed without major complications. Overall manual traction was effective in six patients (8%) and more effective in the ePTFE Group (29%) compared to Group B (0%) and Group C (3%) (P = 0.001). Sixty-seven leads (92%) required mechanical dilatation by the venous entry site approach, with a shorter extraction time in the ePTFE Group (5 ± 11 min) compared to Group B (21 ± 22 min) and Group C (16 ± 22 min) (P = 0.003). ePTFE leads showed a lower rate of fibrotic adherences at the superior vena cava level (P = 0.01) without statistically significant differences in the other sites. Conclusions: ePTFE-covered leads may be removed more easily and quickly than non-ePTFE leads, requiring less frequently mechanical dilatation. (PACE 2010; 33:1376–1381) ePTFE lead, ICD lead extraction, transvenous removal, mechanical dilatation Introduction As the implantable cardiac defibrillator (ICD) patient population expands in size and longevity, the problem of long-term lead-related complications is likely to become more significant. The overall incidence of lead-related complications with transvenous ICD leads, such as infections, malfunctions, or vein occlusion, range from 2% to 28%1 and may require lead extraction. Although techniques and tools for transvenous extraction have been developed for the safe and consistent removal of these leads,2,3 a significant source of difficulty in removal of ICD leads is the fibrosis that forms on the lead body and at the coils. Over time, depending on the insulation material involved, the intravascular portion of the leads Disclosure: None. Address for reprints: Andrea Di Cori, M.D., Division of Cardiovascular Diseases 2, Santa Chiara Hospital, University of Pisa, Pisa, Italy. Fax: 0039050992352; e-mail:
[email protected],
[email protected] Received January 23, 2010; revised April 26, 2010; accepted June 27, 2010. doi: 10.1111/j.1540-8159.2010.02879.x
may become encapsulated,4,5 making subsequent lead extraction difficult. The Endotak Reliance G leads (Guidant Corporation, St. Paul, MN, USA) are steroideluting, endocardial cardioversion/defibrillation, and pace/sense leads available with the electrode coils covered with GORETM expanded polytetrafluoroethylene (ePTFE) to prevent tissue ingrowth around and between the shocking coils.6 Animal investigation study evaluated the extractability of defibrillation leads covered, suggesting that ePTFE may reduce tissue ingrowth facilitating transvenous removal,7 but limited data exist in humans.8 The primary goal of this study was to explore the extractability (success rate and complications, extraction techniques) of ePTFE leads in comparison with standards non-ePTFE ICD leads. In addition, we perfomed a comparative analysis of fibrotic tissue adherences around the leads. Methods Population Study According to our daily practice, baseline patient and lead-related data were consecutively
C 2010 Wiley Periodicals, Inc. C 2010, The Authors. Journal compilation
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collected case-by-case and entered into a computerized database and retrospectively analyzed. Among all ICD leads removed transvenously and collected in our database, we included in the study all the consecutive Endotak Reliance G dual-coil ePTFE leads extracted from the left superior venous entry site (ePTFE Group A). As control groups, we included in the study two models of dual-coil non-ePTFE ICD leads commercially implanted in the same era, with similar physical characteristics but different coil features (Table II), extracted consecutively from the left superior venous entry site in the same period: Sprint QuattroTM 6944 (Medtronic Inc., Minneapolis, MN, USA) (Group B) and RiataTM 1570 (St. Jude Medical, St. Paul, USA) (Group C) leads. Lead Extraction Procedure According to our daily practice, procedural data were consecutively collected case-by-case and entered into a computerized database and retrospectively analyzed. The procedures were performed under local anesthesia or sedation using intravenous propofol and remifentanil. Continuous arterial blood pressure monitoring was performed via an arterial line placed in the left radial artery; a temporary pacemaker was placed in the right ventricle, through a 6-Fr introducer positioned in the left femoral vein. Electrocardiogram and oxygen saturation were monitored during the study. After device removal, the leads were examined visually and by fluoroscopy in their intravascular segment; the proximal end was clipped and standard stylet was introduced. Lead extraction was then attempted using gentle manual traction (MT). If lead traction was unsuccessful, a single sheath mechanical dilatation (MD) technique with a superior approach was used (Cook Intravascular Inc., Leechburg, PA, USA), as previously described.3 From a procedural standpoint, MT was defined as the removal of a lead without using any specific tool. MD was defined as the removal of a lead with the help of mechanical sheaths. Lead extraction time was defined as time since the start of traction to lead removal. Presence of fibrous adherences were firstly measured by the need to use a sheath for extraction (i.e., ineffective MT). Location of fibrous adherences was measured by the operator’s difficulty to advance extraction sheath at five different intravascular site (subclavian, innominate, superior vena cava, tricuspid valve, and ventricle), on the basis of cardiac silhouette and lead course evaluation under fluoroscopic posteroanterior view.9,10
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Statistical Analysis Results are presented as mean ± standard deviation (SD), or frequencies of patients. Parametric continuous variables were reported using means and SDs, and multiple group comparison was performed through an analysis of variance and differences between groups were evaluated using an unpaired two-tailed t-test. Nonparametric continuous variables were reported using median with range and differences between groups were evaluated using a Mann-Whitney U test. Categorical factors were summarized using percentages, the difference between groups was determined using a Person χ 2 -square tests. Statistical analyses were performed using SYSTAT 10.0 software version (Systat Software Inc., Chicago, IL, USA). Statistical significance was defined at P < 0.05. Results Population Study In our database, among 335 ICD leads extracted, we identified 17 consecutive patients with Endotak Reliance G ePTFE leads (ePTFE Group A), who underwent transvenous removal between 2006 and 2009. The group included the following ICD lead models: 14 Reliance G 0175 (passive fixation), one Reliance G 0184 (active fixation), and two Reliance G 0185 leads (active fixation). The control group included 56 patients with conventional ICD leads (non-ePTFE Group B and C) consecutively extracted in the same period. The non-ePTFE groups included 20 polyurethane insulation Sprint QuattroTM 6944 (Medtronic Inc.,) (Group B) and 36 silicone insulation RiataTM 1570 (St. Jude Medical) (Group C). According to the inclusion criteria, all leads had been implanted from the left superior venous entry site. The indication for lead extraction was local infection in 35 patients (48%), sepsis in 24 patients (33%), and lead malfunction in 14 patients (19%). Regarding baseline characteristics, no significant differences were found among groups. Leads features and patient characteristics are shown in Tables I and II. Extraction Outcome All ICD (n = 73) and pacing (n = 94) leads were successfully removed with a left superior venous entry site approach, without complications. Procedural outcomes are shown in Table III. With regard to non-ICD leads, 43 leads were removed using MT and 51 leads using MD. In all three groups, the majority of atrial (57%–77%) and ventricular (60%–100%) pacing leads required MD, whereas the majority of coronary sinus (CS)
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Table I. Patients and Leads Characteristics
Patients – Age (years) – Male (%) – CAD (%) Leads – ICD leads (n) – ICD lead model – Time from implant (months)*
Group A (pTFE) n = 17
Group B (non-pTFE) n = 20
Group C (non-pTFE) n = 36
P Value
66 ± 12 16/17 (94%) 12/17 (70%)
65 ± 12 19/20 (95%) 10/20 (64%)
67 ± 19 28/36 (78%) 23/36 (62%)
NS NS NS
17 Endotak Reliance G 23 ± 26
20 Sprint 6944 26 ± 27
36 Riata 1570 23 ± 17
NS
CAD = coronary artery disease; ICD = implantable cardiac defibrillator; ePTFE = polytetrafluoroethylene. *Data are presented as mean ± SD.
leads were removed by MT (50%–100%), without statistically significant differences among groups. With regard to ICD leads, MT was statistically more effective in the ePTFE Group A than in both the non-ePTFE Groups B and C (29% vs 0% and 29% vs 3%, respectively, P = 0.001). When MT was unsuccesful, MD was effective in all patients. Extraction time was significantly lower in ePTFE Group A in comparison to non-ePTFE Groups B
and C (5 ± 11 vs 21 ± 29 min and 5 ± 11 vs 16 ± 22 min, respectively, P = 0.003) (Fig. 1). Among ePTFE leads extracted by MT, two of five were active fixation leads (Table III). With regard to ICD leads-related adherences, they were found in 67 (92%) of 73 patients. In all groups, the mean location rate was higher proximally (subclavian vein [SV], innominate vein [IV], and superior vena cava [SVC]) rather than
Table II. ICD Lead Model Features
Model Manufacturer Lead body diameter (mm) Isodiametric Lead design External insulation Sensing Coil number Coil surface area (mm2 ) - Proximal - Distal Tip to proximal coil (cm) Shocking conductor Coil wire Coil backfilling Coil covering Fixation Steroid eluting
Group A
Group B
Group C
Endotak Reliance G Boston 2.7 Yes Multilumen Silicone Integrated Dual
Sprint Quattro 6944 Medtronic 2.7 Yes Multilumen Polyurethane True bipolar Dual
Riata 1570 St. Jude Medical 2.7 No Multilumen Silicone True bipolar Dual
660 450 18 Drawn brazed strand cable Rounded No ePTFE Active/passive Yes
819 585 18 Platinum alloy-clad tantalum Flat Yes No Passive Yes
663 414 17 Platinum-iridium Rounded No No Passive Yes
ePTFE = polytetrafluoroethylene.
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Table III. Procedural Outcomes Group A (ePTFE) n = 17
Group B (non-ePTFE) n = 20
Group C (non-ePTFE) n = 36
P Value
9/17 (53%) 6/17 (35%) 2/17 (12%)
13/20 (65%) 3/20 (15%) 4/20 (20%)
13/36 (36%) 15/36 (45%) 7/36 (19%)
NS NS NS
25/25 (100%) 17/17 (100%)
24/24 (100%) 20/20 (100%)
45/45 (100%) 36/36 (100%)
None
None
None
5/17 (29%)† 12/17 (71%)† 5 ± 11†
0/20 (0%) 20/20 (100%) 21 ± 29
1/36 (3%)‡ 35/36 (97%)‡ 16 ± 22‡
Procedural indication - Local infection (%) - Systemic infection (%) - Malfunction (%) Procedural outcomes Complete removal, n (%) - Non-ICD leads - ICD leads Complications - Major ICD leads procedural data - Manual traction (n) - Dilatation (n) - Extraction time (min.)§ Removal technique Cardiac leads per patients§ ICD leads, n (%) Non-ICD leads, n - Atrial, n (%) - Ventricular Pacing, n (%) - CS leads, n (%)
0.001 0.04 0.003
MT
MD
MT
MD
MT
MD
2.6 ± 0.9 5 (29%)* 14 6 (43%) 8 (100%)
2 ± 1.2 12 (71%)** 11 8 (57%) 3 (100%) -
8 3 (23%) 2 (40%) 3 (50%)
2.2 ± 1 20 (100%) 16 10 (77%) 3 (60%) 3 (50%)
4*** 1 (3%) 21 5 (25%) 1 (20%) 15 (75%)
2.1 ± 1.1 35 (97%) 24 15 (75%) 4 (80%) 5 (25%)
NS
NS NS NS
CS = coronary sinus; ePTFE = polytetrafluoroethylene; ICD = implantable cardiac defibrillator; MD = mechanical dilatation; MT = manual traction; SVC = superior vena cava. *Two screw-in lead. **One screw-in lead. ***One patient. †Comparison between A and B (P < 0.05). ‡Comparison between C and A (P < 0.05). §Data are presented as mean ± SD.
distally (right atrium [RA] and tricuspid valve [TV]). Respect to non-ePTFE Groups B and C, the ePTFE Group A showed a statistically significant lower adherences rate only at the SVC level (35% vs 58% and 35% vs 78%, respectively, P = 0.01). At the other sites (SV, IV, RA, TV, and right ventricle [RV]), even if ePTFE leads showed lower mean adherence rates, no statistically significant differences were found (P = NS) (Fig. 2). Discussion The present study describes adherence rates and location, and extraction performance of dualcoil ePTFE leads in comparison to conventional ones in humans. In the pioneering experimental
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study by Wilkoff et al.,7 subjects received either unmodified leads that served as controls, leads that were modified by backfilling the shocking coil filars with medical adhesive, or leads that were modified by coating the shocking coil with ePTFE. None of the ePTFE leads had fibrotic tissue attachment to the shocking coils but one required the use of an extraction sheath to be removed because of tissue attachment to the lead tip. In our experience, although the extraction success rate was comparable (100%) among groups, we documented a more effective MT and a statistically significant lower extraction time in the ePTFE patients. Moreover, the ePTFE group showed a significantly lower adherences rate at the SVC
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Figure 1. Extraction time comparison between groups. Group A (ePTFE leads) showed a mean lower extraction time compared to Group B (Sprint Quattro) and Group C (Riata 1570). ePTFE = polytetrafluoroethylene.
level (site of SVC shock coil) and a mean lower (but not statistically significant) rate at the right ventricular level (site of RV shock coil). In general, ICD leads (especially older models) are considered more difficult to extract because of their larger size, aggressive fibrosis around the coils, and sometimes nonisodiametric structure. In addition, they also contains single or dual
Figure 2. Fibrotic adherences rate and location. With respect to Group B (Sprint Quattro) and Group C (Riata 1570), Group A (ePTFE leads) showed a statistically significant lower rate at the SVC level and a mean lower value at (but not statistically significant) at the other sites. IV = innominate vein; ePTFE = polytetrafluoroethylene; RA = right atrium; RV = right ventricle; SV = subclavian vein; TV = tricuspid valve; SVC = superior vena cava.
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high-voltage shock coils that allow the delivery of defibrillation therapy to the cardiac tissue.11 With regard to shocking coils, they present a large surface area in contact with the blood, endocardium, and vascular structures. A bare metal coil wire structure is a disadvantage with ICD leads as a marked fibrous reaction occurs following implantation, resulting in tissue encapsulation of the lead body. At points where the coil wires make contact with endocardial or endothelial tissues, fibrous tissue ingrowths occur particularly in the interstices between helical turns of the coiled wire, which in time with collagen maturation and contracture firmly anchors the lead to the venous vasculature or the endocardial wall. Today’s lead designs use several extra-coil insulating materials as silicone, polyurethane, and fluoropolymers (ePTFE, Ethylene Tetrafluoroethylene).12 The nonePTFE lead evaluated in the control groups, even if different in terms of external insulation and noncovered coil design, did not show significative differences for adherences location and rate. Although the larger Sprint Quattro coil surface areas (Table II) may account for the observed performance of the flat wire coil technology with silicone backfilling (i.e., not reduced cell penetration and tissue ingrowth with respect to standard rounded not backfilled Riata 1570 leads), we should consider that full silicone backfilling cannot be achieved because of the necessity to leave a bare high surface area voltage interface with the tissues. Thus, ingrowth may be still observed, making an extraction attempt difficult and dangerous.13,14 The Endotak Reliance G lead has a silicone insulator and a coil design that incorporates a 20μm thin sheath of ePTFE (Gore-Tex; W.L. Gore and Associates, Flagstaff, AZ, USA). Unlike other fluoropolymers used in ICD leads, the expanded porous ultrastructure of the polymer allows fluid ingress, thus making the material effectively electrically conductive, but does not allow cellular migration, avoiding tissue ingrowths over the bare coils. In this study, we did not find differences in adherence location among groups, except for the SVC, where the proximal coil is usually placed. This could suggest that the ePTFE coil, but not the extra-coil lead insulation material, affects significantly fibrotic ingrowth and adherence location. With regard to non-ICD leads, according to our experience,3 while CS leads were removed almost by MT, atrial and ventricular pacing leads required predominantly MD. Although the presence of multiple leads with anatomical interactions and adherences may theoretically account for the ICD leads success rate removal and the need for dilatation, among groups we did not find significant differences in
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terms of total leads per patient, ICD leads removal technique required, and outcomes. Finally, two of five ePTFE leads removed by MT were active fixation. Although a potential lower rate of adherences at the tip level of active fixation leads could be hypothesized, it is unlikely that screwin technology might account for fibrosis reduction at extra-tip critical sites (es. SVC) and necessity for MD. However, on the basis of the present study, no conclusive statements can be made about the role of active fixation technology for ePTFE leads. This study found that, in humans, an ePTFE coating that minimizes tissue ingrowth may significantly enhance the extractability of ICD leads. Although long-term data evaluating ease of extraction remain to be seen, prevention of tissue ingrowth could not only facilitate lead extraction but also reduce procedural complications. ePTFE leads might be especially attractive and advantageous in patient populations with a long life expectancy, where a longer overall survival increases the cumulative risk of lead failure or infection and the consequent need for lead extraction. Study Limitations The study presented several limitations. First, the study population was relatively small, but, to verify the study hypothesis, we believed it necessary to compare ePTFE leads with two control groups of non-ePTFE leads commercially implanted in the same era, with similar physical
characteristics but different coil features. Second, the investigation was designed as a case-control study. A prospective trial to evaluate prognostic implications of ePTFE-leads extraction compared to traditional leads is desirable, but a very large number of patients would need to be enrolled to obtain meaningful results. Third, we did not include gross examination and histopathology of the extracted leads, but, considering that the aim was to evaluate the extraction leads profile from a procedural perspective, it was beyond the intentions of the present study. Finally, the study included a small group of ICDs with specific patients and lead features (low implantation time, left-side implantation, dual coil) referred for device removal. Thus, real prevalence of areas of fibrous adherences and the related extraction performance in this patient population could not be representative for all ICD patient population. Long-term data evaluating ease of extraction of this lead remain to be seen. Conclusions With respect to conventional ICD leads, ePTFE-covered leads seem to provoke less intracardiac tissue ingrowth and adherences, offering a better extraction performance. Prevention of tissue ingrowth, as has been demonstrated with the ePTFE leads, could reduce the risk associated with extraction of ICD leads. This type of lead may be even more attractive in specific patient populations with high risk of future complications and need for lead removal.
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7. Wilkoff BL, Belott PH, Love CJ, Scheiner A, Westlund R, Rippy M, Krishnan M, et al. Improved extraction of ePTFE and medical adhesive modified defibrillation leads from the coronary sinus and great cardiac vein. Pacing Clin Electrophysiol 2005; 28:205–211. 8. Kouht AR, Rafeek J, Grammes J, Saari CS, Schulze CM, Yesenosky GA, Aquilina PM, et al. The ePTFE-coated ICD leads are easier to remove than standard ICD leads up to 50 months implant duration. Heart Rhythm 2009; 6:S132–S133 (abstract). 9. Smith HJ, Fearnot NE, Byrd CL, Wilkoff BL, Love CJ, Sellers TD. Five-years experience with intravascular lead extraction. U.S. Lead Extraction Database. Pacing Clin Electrophysiol 1994; 17(11 Pt. 2):2016–2020. 10. Bongiorni MG, Zucchelli G, Soldati E, Arena G, Giannola G, Di Cori A, Lapira F, et al. Usefulness of mechanical transvenous dilation and location of areas of adherence in patients undergoing coronary sinus lead extraction. Europace 2007; 9:69–73. 11. Haqqani HM, Mond HG. The implantable cardioverter-defibrillator lead: Principles, progress, and promises. Pacing Clin Electrophysiol 2009; 32:1336–1353. 12. Gradaus R, Breithardt G, Bocker D. ICD leads: Design and chronic ¨ dysfunctions. Pacing Clin Electrophysiol 2003; 26(2 Pt. 1):649–657. 13. Smith MC, Love CJ. Extraction of transvenous pacing and ICD leads. Pacing Clin Electrophysiol 2008; 31:736–752. 14. Verma A, Wilkoff BL. Intravascular pacemaker and defibrillator lead extraction: A state-of-the-art review. Heart Rhythm 2004; 1:739– 745.
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